Development of DBF radars

DBF (digital beam forming) radars using T/R(transmit/receive) modules were developed. For realizing DBF, there are three important technologies, phase detection technology, multi-beam forming technology and adaptive beam forming technology. In order to establish these key technologies, the DBF array test equipment was manufactured. These technologies and the data of the test equipment are presented. In order to realize high DBF performance, it is necessary to convert antenna element signals to digital signals with high accuracy. In order to solve this problem, an IF (intermediate frequency) direct sampling phase detection method is used with uniquely developed LSI. Regarding multi-beam forming, very high speed circuits are necessary in a radar application. The systolic array method is applied. In the systolic array, arbitrary and independently controlled multi-beams can be formed by controlling complex weights of each beam. In the DBF technology, an adaptive technique can easily be applied. The systolic array using the Gram-Schmidt transformation method is applied. This adaptive circuit was developed and tested in an open site. The jammers were transmitted and the antenna patterns were measured before and after adaptation